Bifunctional agents possessing antioxidant and antiarrhythmic activity

ABSTRACT

The present invention relates to novel bifunctional agents possessing antioxidant and antiarrhytmic activity, methods for the synthesis of the same and their applications in treating ischemia-reperfusion injury, as well as a variety of disorders related to free radicals and/or arrhythmias. These bifunctional drugs should prefrentially segregate in the membrane and produce their antiarrhytmic effects while, at the same time, help in protecting the membrane lipids by scavenging free radicals. The present invention comprises compounds represented by Formula (I), wherein R 1 , R 2 , R 3 , R 4 , R 5  are further defined.

FIELD OF THE INVENTION

[0001] The present invention relates to novel bifunctional agentspossessing antioxidant and antiarrhythmic activity, methods for thesynthesis of the same and their applications in treatingischemia-reperfusion injury, as well as a variety of disorders relatedto free radicals and/or arrhythmias.

BACKGROUND OF THE INVENTION

[0002] The majority of life threatening ventricular arrhythmias occur inpatients suffering from ischemic heart disease. Reperfusion(reoxygenation) of the ischemic heart tissue and administration ofantiarrhythmic drugs, follow the case of myocardial infarctions. Howeverthe use of antiarrhythmic drugs to suppress arrhythmias and preventsudden cardiac death has limited success (Woosley R. L. “Antiarrhythmicdrugs” Annu. Rev. Pharmacol. Toxikol. 1991, 31, 427).

[0003] Accumulated evidence suggests that the injury sustained by theheart, following a case of acute myocardial ischemia occurs duringreoxygenation. It is believed that the biochemical changes occurringduring the ischemic period produce a burst of active oxygen species(AOS) when molecular oxygenation is reintroduced (McCord J. M.“Oxygen-derived free radicals in postischemic tissue injury” N. Engl. J.Med. 1985, 312, 159). These oxygen radicals include superoxide (O²⁻)which is a precursor of several more toxic radicals such as hydroxylradical (OH). It is postulated that these free radicals react with thephospholipid components of myocardium. Such reactions affect theselective permeability of cell membranes and are related to thedevelopment of life threatening ventricular arrhythmias and/orfibrillation. Under normal conditions cells are protected from suchreactions by various enzymes and by some small molecules which arenormally involved in cellular redox reactions. However, thesebiochemical processes are inadequate during hypoxic conditions.Treatment with antioxidants such as α-tocopherol has been shown toreduce membrane related alterations resulting from ischemia andreperfusion, (Massey K. D., Burton K. P. “α-Tocopherol attenuatesmyocardial membrane-related alterations resulting from ischemia andreperfusion” Am. J. Physiol. 1989, 256, H1192).

[0004] Accordingly, it would be advantageous to develop bifunctionalagents which will act as antiarrhythmic antioxidants. These bifunctionaldrugs should preferentially segregate in the membrane and produce theirantiarrhythmic effects while, at the same time, help in protecting themembrane lipids by scavenging free radicals.

[0005] Thus the pharmacophore backbone of structural analogs of vitaminE and key features responsible for the antiarrhythmic properties ofclass I or class III antiarrhythmics were combined in one molecularscaffold. Lipophilic features have been incorporated in order to achievefavorable partitioning in the myocardial membranes.

[0006] The molecular design also has taken into account all availableinformation on structure activity relationships for optimalantiarrhythmic activity with minimal undesirable effects.

SUMMARY OF THE INVENTION

[0007] The present invention comprises compounds represented by FormulaI.

[0008] X═CH₂, NC(O)CH₂N R′R″, CHNHC(O)CH₂NR′R″, NC(O)R′″, CHNHC(O)R′″,n=1

[0009] X═CH₂, n=0

[0010] R₁=H, alkyl, alkenyl, alkynyl, aryl all of which may beoptionally substituted

[0011] R₂=Alkyl, aryl, C(O)NH(CH₂CH₂)_(m)NR′R″, C(O)Y C(O)R′″,CH₂Y(CO)R′″

[0012] CH₂YCH₂R′″ with the proviso that when X═CH₂, n=1, R₁=R₃=R₄=R₅=Meto R₂ can not be C(O)NHCH₂CH₂ N(Me)₂

[0013] R₃=Alkyl, C(O)NH(CH₂CH₂)_(m)N R′R″, NHC(O)CH₂N R′R″, NHC(O)R′″

[0014] R₄, R₅=Lower alkyl

[0015] Y=HN(CH₂CH₂)_(m)NH, HNCHR₁NH, HN-cycloalkyl-NH, HN-aryl-NH,heterocyclic diamine, m=1-5

[0016] R′; R″=Alkyl

[0017] R′″=(methylsulfonyl)amino-N-aryl

[0018] In accordance with the present invention and as used herein, thefollowing terms, when appearing alone or as part of a moiety, aredefined with the following meaning, unless explicitly stated otherwise.

[0019] The term “alkyl,” as used herein at all occurrences, refers tosaturated aliphatic groups including straight chain, branched chain, andcyclic groups, all of which may be optionally substituted. Preferredalkyl groups contain 1 to 16 carbon atoms.

[0020] The term “alkenyl,” as used herein at all occurrences, refers tounsaturated groups which contain at least one carbon-carbon double bondand includes straight chain, branched chain, and cyclic groups, all ofwhich may be optionally substituted. Preferable alkenyl groups have 2 to16 carbon atoms.

[0021] The term “alkynyl,” as used herein at all occurrences, refers tounsaturated hydrocarbon groups which contain at least one carbon-carbontriple bond and includes straight chain and branched chain groups whichmay be optionally substituted. Preferred alkynyl groups have two tosixteen carbon atoms.

[0022] The term “aryl” refers to aromatic groups which have at least onering having a conjugated π electron system and includes carbocyclic aryland biaryl, both of which may be optionally substituted. Preferred arylgroups have 6 to 10 carbon atoms.

[0023] The term “optionally substituted” or “substituted,” unlessotherwise specifically defined herein, refers to groups substituted byone to five substituents, independently selected from lower alkyl(acyclic and cyclic), aryl (carboaryl and heteroaryl), alkenyl, alkynyl,alkoxy, halo, haloalkyl (including trihaloalkyl, e.g. trifluoromethyl),amino, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, nitro,alkanoyl, alkanoyloxy, alkanoyloxyalkanoyl, alkoxycarboxy, carbalkoxy,carboxamido, formyl, carboxy, hydroxy, cyano, azido, keto and cyclicketals thereof, alkanoylamido, heteroaryloxy.

[0024] The term “lower” is referred to herein in connection with organicradicals or compounds defines one up to and including six. Such groupsmay be straight chain, branched chain, or cyclic.

[0025] The present invention includes all possible stereoisomers ofFormula I and includes not only racemic compounds but also the opticallyactive isomers as well. Some specific compounds of Formula I are listedbelow, the synthesis of which was performed in accordance with theExample Section set forth below.

[0026]N-(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-carbonyl)-N′,N′-diethylethylenediamine

[0027]N-(3,4-dihydro-6-hydroxy-2-hexyl-5,7,8-trimethyl-2H-1-benzopyran-2-carbonyl)-N′,N′-diethylethylenediamine

[0028]N-(3,4-dihydro-2-dodecyl-6-hydroxy-5,7,8-trimethyl-2H-1-benzopyran-2-carbonyl)-N′,N′-diethylethylenediamine

[0029]N-(3,4-dihydro-6-hydroxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0030]N-(3,4-dihydro-6-hydroxy-2-hexyl-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0031]N-(3,4-dihydro-2-dodecyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0032]N-(3,4-dihydro-6-hydroxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide

[0033]N-(3,4-dihydro-2-hexyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide

[0034]N-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran-4-yl)-(diethylamino)acetamide

[0035]N-(3,4-dihydro-2-hexyl-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyrany-4-yl)-(diethylamino)acetamide

[0036] Synthesis of any compounds of the Formula I not specifically setforth herein can be accomplished by methods analogous those illustratedin Schemes (A-D) set forth below as well as the methods described in theExample section.

[0037] Compound a (R=Me) was prepared from trolox andN,N-diethylethylenediamine in the presence of CDI (Jacobsen E. J.,VanDoornik F. J., Ayer D. E., Belonga K. L., Braughler J. M., Hall E.D., Houser D. J. “2-(Aminoethyl)chromans that inhibit iron-dependentlipid peroxidation and protect against central nervous system trauma andischemia” J. Med. Chem. 1992, 35, 4464). Compounds b,c containing longeralkyl chains at position 2 of the chroman moiety were synthesized from6-hydroxychroman-2-carbonitriles 1 (prepared by the methods described by(Janero D. A., Cohen N., Burghardt B., Schaer B. H. “Novel6-hydroxychroman-2-carbonitrile inhibitors of membrane peroxidativeinjury” Biochem. Pharmacol. 1990, 40, 551). Alkaline hydrolysis of thenitriles afforded the acids 2 which were in turn converted to thecorresponding acid chlorides and subsequently to the6-hydroxy-chroman-2-amides (Scheme A).

[0038] 6-Methoxy-2-methyl-2-alkylchromans 3 [prepared by condensation of2,3-dimethylhydroquinone with the appropriate allylalcohol (Mukai K.,Kageyama Y., Ishida T., Fukuda K. “Synthesis and kinetic study ofantioxidant activity of new tocopherol compounds” J. Org. Chem. 1989,54, 552) and methylation of the resulting6-hydroxy-2-methyl-2-alkylchromans] were used as starting materials forthe synthesis of the compounds d-h (Schemes B,C).

[0039] Formylation of 3 (Schuda P. F., Price W. A. “Total synthesis ofisoflavones. Friedel-Crafts Acylation reactions with acid sensitivesubstrates” J. Org. Chem. 1987, 52, 1972) gavel the 5-chromanaldehydes 4which were in turn converted to the corresponding acids 5 by oxidationwith sodium chlorite-hydrogen peroxide (Dalcanale E., Montanari F.“Selective oxidation of aldehydes to carboxylic acids with sodiumchlorite-hydrogen peroxide” J. Org. Chem. 1986, 51, 567). The acids werethen converted to acid chlorides which upon reaction with N,N-diethylethylenediamine and deprotection of the methoxy group gave the amidesd-f (Scheme B).

[0040] Nitration if 3 using acetyl nitrate (Ohkawa S., Fukatsu K., MikiS., Hashimoto T., Sakamoto J., Doi T., Nagai Y., Aono T.“5-aminocoumarans: Dual inhibitors of lipid peroxidation and dopaminerelease with protective effects against central nervous system traumaand ischemia” J. Med. Chem. 1997, 40, 559) followed by reduction of theresulting 5-nitrochroman (Ono A., Hiroi M., Shimazaki K. “Reduction ofaromatic nitro-compounds by the sodium borohydride-copper (I) chloridesystem” Chem. Ind. 1984, 75) afforded the corresponding amines 8 whichwere acylated using bromoacetyichloride. Reaction of bromoamides 9 withdiethylamine (Phillips G. B., Morgan T. K., Nickish K., Lind J. M.,Gomez R. P., Wohl R. A., Argentieri T. M., Sullivan M. E. “Synthesis andcardiac electrophysiological activity of aryl-substituted derivatives ofthe, class III antiarrhythmic agent sematilide.” Med. Chem. 1990, 33,627) followed by deprotection of the methoxy group gave the amides g,h(Scheme C).

[0041] For the synthesis of amides 1, j 3,6-dihydroxy-2,4,5-trimethylacetophenone (11) (Pearce B. C., Parker R. A., Deason M. E., Dischino D.D., Gillepsie E., Qureshi A. A., Volk K., Wright K. J. J. “Inhibitors ofcholesterol biosynthesis. 2. Hypocholisteronemic and antioxidantactivities of benzofuran and tetrahydronaphthalene analogs of thetocotrienols” J. Med. Chem. 1994, 37, 526) was reacted with thecorresponding methyl ketone in the presence of pyrrolidine to givechromanones 12 which were converted to oximes 13 (Phillips G. B., MorganT. K., Nickish K., Lind J. M., Gomez R. P., Wohl R. A., Argentieri T.M., Sullivan M. E. “Synthesis and cardiac electrophysiological activityof aryl-substituted derivatives of the class III antiarrhythmic agentsematilide.” J. Med. Chem. 1990, 33, 627). Reduction using TiCl₄/NaBH₄afforded amines 14 (Kano S., Tanaka Y., Sugino E., Hibino S. “Reductionof some functional groups with titanium(IV) chloride/sodiumborohydride”. Synthesis 1980, 695) which were acylated using bromoacetylchloride to afford amides 15. Reaction of amides 15 with diethylamineafforded compounds i,j.

[0042] The present invention also includes the pharmaceuticallyacceptable salts of the compounds of Formula I as well as pharmaceuticalformulations containing these compounds.

GENERAL PROCEDURES

[0043] NMR spectra were recorded on a Bruker AC 300 spectrometeroperating at 300 MHz for ¹H and 75.43 MHz for ¹³C. ¹H NMR spectra arereported in units of δ relative to internal CHCl₃ at 7.24 ppm. ¹³C NMRshifts are expressed in units of δ relative to CDCl₃ at 77.0 ppm. ¹³CNMR spectra were proton noise decoupled. All NMR spectra were recordedin CDCl₃. Silica gel plates (Merck F254) were used for thin layerchromatography. Chromatographic purification was performed with silicagel (200-400 mesh).

General Procedure for the Preparation of3,4-dihydro-6-hydroxy-2-alkyl-5,7,8-trialkyl-2H-1-benzopyran-2-carboxylicacids

[0044] 4.65 mmol of the appropriate nitrile were added to a solution of20 mL 85% KOH in ethyleneglycol and the mixture was refluxed overnight.The solvent was then removed in vacuo and the residue dissolved in coldwater. The solution was acidified with 2N HCl and extracted with AcOEt.The3,4-dihydro-6-hydroxy-2-alkyl-5,7,8-trialkyl-2H-1-benzopyran-2-carboxylicacid was recrystallized from AcOEt/pet. ether (40-60).

EXAMPLE 13,4-dihydro-2-hexyl-6-hydroxy-5,7,8-trimethyl-2H-1-benzopyran-2-carboxylicacid

[0045] Use of3,4dihydro-6-hydroxy-2-hexyl-5,7,8-trimethyl-2H-1-benzopyran-2-carbonitrileas employed above afforded 1.18 g (79.1%) of the desired compound namedabove: ¹H NMR δ 4.42 (s, 1H), 2.64-2.57 (m, 2H), 2.33-2.28 (m, 1H), 2.17(s, 6H), 2.11 (s, 3H), 1.9-1.85 (m, 1H), 1.5-1.25 (m, 10H), 0.86 (t,J=6.3 Hz, 3H); ¹³C NMR δ 176.9, 145.7, 144.2, 81.0, 37.0, 31.8, 29.4,28.8, 23.4, 22.6, 20.4, 14.1, 12.3, 11.9, 11.3; Anal. (C₁₉H₂₈O₄) C,H.

EXAMPLE 23,4-dihydro-2-dodecyl-6-hydroxy-5,7,8-trimethyl-2H-1-benzopyran-2-carboxylicacid

[0046] Use of3,4-dihydro-6-hydroxy-2-dodecyl-5,7,8-trimethyl-2H-1-benzopyran-2-carbonitrileas employed above afforded 1.39 g (73.8%) of the desired compound namedabove: ¹H NMR δ 2.62-2.59 (m, 2H), 2.4-2.2 (m, 1H), 2.18 (s, 1H), 2.18(s, 3H), 2.09 (s, 3H), 1.91-1.86 (m, 1H), 1.5-1.24 (m, 22H), 0.88 (t,J=6.3 Hz, 3H); Anal. (C₂₅H₄₀O₄) C,H.

General Procedure for the Preparation of N(3,4-dihydro-6-hydroxy-2,5,7,8-tetraalkyl-2H-1-benzopyran-2-carbonyl)-N′,N′-dialkyl-ethylenediamines

[0047] 1,1′-carbonyidiimidazole (537 mg, 3.3 mmol) was added to asolution of chroman carboxylic acid (3 mmol) in 15 mL THF. Afterstirring for 1 h at RT, a solution of N, N, dialkyl ethylenediamine in12 mL THF was added dropwise. The mixture was allowed to stir for 24 hat RT. The solvent was then evaporated in vacuo and the residue wastaken up with ethyl acetate and the organic layer was washed with brineand dried (Na₂SO₄).

EXAMPLE 3N-(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-carbonyl)-N′,N′-diethylethylenediamine

[0048] Use of trolox (750 mg, 3 mmol) as employed above afforded 0.73 g(70%) of the desired compound named above: ¹H NMR δ 7.13 (bs, 1H),3.28-3.18 (m, 2H), 2.59-2.31 (m, 9H), 2.18 (s, 3H), 2.17 (s, 3H), 2.16(s, 3H), 1.89-1.85 (m, 1H), 1.50 (s, 3H), 0.90 (t, J=7.2 Hz, 6H); ¹³CNMR δ 174.3, 145.5, 144.3, 121.9, 121.6. 119.1, 117.6, 78.1, 51.3, 46.4,36:5, 29.4, 24.4, 20.5, 12.2, 11.9, 11.7, 11.3; Anal. (C₂₀H₃₂N₂O₃)C,H,N.

EXAMPLE 4N-(3,4-dihydro-2-hexyl-6-hydroxy-5,7,8-trimethyl-2H-1-benzopyran-2-carbonyl)-N′,N′-diethyl ethylenediamine

[0049] Use of 3,4-dihydro-2-hexyl-6-hydroxy-5,7,8-trimethyl-2H-1-benzopyran-2-carboxylic acid as employed aboveafforded 0.308 g (65.5%) of the desired compound named above: ¹H NMR δ7.10 (bs, 1H), 4.5(bs, 1H), 3.37-3.29 (m, 2H), 2.61-2.49 (m, 6H),2.29-2.2 (m, 1H), 2.16 (s, 3H), 2.11 (s, 3H), 2.05 (s, 3H), 1.95-1.69(m, 3H), 1.44-1.23 (m, 10H), 1.0 (t, J=7 Hz, 6H), 0.84 (t, J=6.3 Hz,3H); ¹³C NMR δ 175.3, 146.2, 143.1, 122.5, 121.9, 119.6, 117.2, 80.4,51.2, 46.9, 37.8, 36.3, 31.4, 29.1, 28.4, 23.1, 22.3, 20.0, 13.8, 12.1,11.8, 11.7, 11.2

EXAMPLE 5N-(3,4-dihydro-2-dodecyl-6-hydroxy-5,7,8trimethyl-2H-1-benzopyran-2-carbonyl)-N′,N′-diethylethylenediamine

[0050] Use of3,4-dihydro-6-hydroxy-2-dodecyl-5,7,8-trimethyl-2H-1-benzopyran-2-carboxylicacid as employed above afforded 0.323 g (58.4%) of the desired compoundnamed above: ¹H NMR δ 7.15 (bs, 1H), 4.6 (bs, 1H), 3.36-3.34 (m, 2H),2.61-2.43 (m, 6H), 2.29-2.22(m, 1H), 2.17 (s, 3H), 2.13 (s, 3H), 2.05(s, 3H), 2.01-1.73 (m 3H), 1.44-1.23 (m, 22H), 1.01 (t, J=7.1 Hz, 6H),0.87 (t, J=6.1 Hz, 3H); ¹³C NMR δ 175.7, 146.1, 143.3, 122.4, 121.9,119.6, 117,5, 80.7, 50.0, 47.6, 47.4, 36.6, 34.8, 31.8, 29.5, 29.3,29.2, 28.4, 23.3, 22.5, 20.1, 13.9, 12.4, 11.9, 11.5

General Procedure for the Preparation of3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-carboxaldehydes

[0051] To a solution of the appropriate3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran (5.45 mmol) in4 mL CH₂Cl₂ was added α,α-chloromethyl methyl ether (1.2 mL, 14.5 mmol).The mixture was cooled to 0° C. and a solution of TiCl₄ (0.8 mL, 7.8mmol) in 4 mL CH₂Cl₂ was added dropwise. The resulting mixture wasstirred at RT for 2 h, poured into ice, extracted with CH₂Cl₂ and theorganic layer was washed with sat. aqu. NaHCO₃, brine and dried(Na₂SO₄).

EXAMPLE 63,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carboxaldehyde

[0052] Use of 3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyranas employed above afforded 1.35 g (100%) of the desired compound namedabove: ¹H NMR δ 10.49 (s, 1H), 3.76 (s, 3H), 3.09 (t, J=6.5 Hz, 2H), 2.2(s, 3H), 2.16 (s, 3H), 1.73 (t, J=6.2 Hz, 2H), 1.29 (s, 6H)

EXAMPLE 73,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carboxaldehyde

[0053] Use of3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran asemployed above afforded 1.56 (90%) of the desired compound named above:¹H NMR δ 10.47 (s, 1H), 3.74 (s, 3H), 3.05 (t, J6.4 Hz, 2H), 2.19 (s,3H), 2.15 (s, 3H), 1.8-1.6 (m, 2H), 1.55-1.51 (m, 2H), 1.36-1.25 (m,8H), 1.22 (s, 3H), 0.85 (t, J=6.8 Hz, 3H); ¹³C NMR δ 193.0, 156.5,148.0, 134.4, 128.8, 124.0, 120.1, 75.6, 63.5, 39.5, 31.8, 30.8, 29.8,23.8, 23.5, 22.6, 21.1, 14.0, 13.0, 11.9; Anal. (C₂₀H₃₀O₃) C,H.

EXAMPLE 83,4-dihydro-2-dodecyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carboxaldehyde

[0054] Use of3,4-dihydro-2-dodecyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran asemployed above afforded 2.19 g (100%) of the desired compound namedabove: ¹H NMR δ 10.48 (s, 1H), 3.75 (s, 3H), 3.06 (t, J=7 Hz, 2H), 2.20(s, 3H), 2.16 (s, 3H), 1.76-1.55 (m,2H), 1.54-1.49 (m, 2H), 1.40-1.25(m, 20H), 1.23 (s, 3H), 0.86 (t, J=6.7 Hz, 3H); Anal. (C₂₅H₄₂O₃) C,H.

General Procedure for the Preparation of3,4-dihydro-6ethoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-carboxylicacids

[0055] A solution of NaClO₂ 80% (800 mg, 7 mmol) in 7 mL H₂O was addeddropwise to a stirred mixture of the appropriate3,4dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyrancarboxaldehyde (4mmol), NaH₂PO₄.H₂O (160 mg, 1.3 mmol), 0.5 mL H₂O₂ 35% and 2 mL H₂O and10 mL MeCN at 10° C. The mixture was stirred at RT overnight.Subsequently, 50 mg of Na₂SO₃ were added to destroy HOCl and excess H₂O₂and the aqueous phase was extracted with CH₂Cl₂. The organic phase waswashed with 2N NaOH. Acidification of the aqueous phase (conc. HCl) andextraction with CH₂Cl₂ afforded the title compounds.

EXAMPLE 93,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carboxylicacid

[0056] Use of3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carboxaldehydeas employed above afforded 0.760 g (72%) of the desired compound namedabove: ¹NMR δ 11.0 (bs, 1H), 3.77 (s, 3H), 2.93 (t, =J6.7 Hz, 2H), 2.19(s, 3H), 2.13 (s, 3H), 1.76 (t, J=6.7 Hz, 2H), 1.31 (s, 6H); Anal.(C₁₅H₂₀O₄) C,H.

EXAMPLE 103,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-6-carboxylicacid

[0057] Use of3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carboxaldehydeas employed above afforded 1.24 g (93%) of the desired compound namedabove: ¹H NMR δ 3.67 (s, 3H), 2.8-2.7 (m,2H), 2.12 (s, 3H), 2.06 (s,3H), 1.6-1.4 (m, 4H), 1.4-1.25 (m, 8H), 1.17 (s, 3H), 0.85 (to J=6.5 Hz,3H)

EXAMPLE 113,4-dihydro-2-dodecyl-6-methoxy-2,7,8trimethyl-2H-1-benzopyran-5-carboxylicacid

[0058] Use of3,4-dihydro-2-dodecyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carboxaldehydeas employed above afforded 1.60 g (96%) of the desired compound namedabove: ¹H NMR δ 3.76 (s, 3H), 2.95 (to J=6.6 Hz, 2H), 2.19 (s, 3H), 2.13(s, 3H), 1.74-1.37 (m, 4H), 1.35-1.24 (m, 20H), 1.23 (s, 3H), 0.87 (t,J=6.2 Hz, 3H)

General Procedure for the Preparation ofN-(3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-carbonyl)-N′,N′dialkylethylene diamines

[0059] To a solution of the appropriate3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-carboxylicacid (1.9 mmol) in 5 mL benzene was added SOCl₂ (0.6 mL, 7.5 mmol) andthe mixture was refluxed for 2 h. The solvent and the excess thionylchloride were removed in vacuo. The residue was then diluted with 7 mLTHF, N,N-dialkylethylenediamine was added and the mixture was stirredovernight at RT. The solvent was then evaporated, the residue was takenup with AcOEt and the organic layer was washed with brine. The crudeproduct was purified by flash column chromatography (CH₂Cl₂/MeOH)

EXAMPLE 12N-(3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamline

[0060] Use of3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carboxylicacid as employed above afforded 0.51 g (74.5%) of the desired compoundnamed above: ¹H NMR δ 6.67 (bs, 1H), 3.67 (s, 3H), 3.62-3.56 (m, 2H),2.73 (t, J=6.4 Hz, 2H), 2.71-2.63 (m, 6H), 2.15 (s, 3H), 2.09 (s, 3H),1.72 (t, J=6.7 Hz, 2H), 1.3 (s, 6H), 1.09 (t, J=7.2 Hz, 6H); Anal.(C₂₁H₃₄N₂O₃).0.5H₂O C,H,N.

EXAMPLE 13 N-(3,4-dihydro-2-hexyl-6-methoxy2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0061] Use of3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carboxylicacid as employed above afforded 0.68 g (82.5%) of the desired compoundnamed above: ¹H NMR δ 6.8 (bs, 1H), 3.63 (s, 3H), 3.61-3.57 (m, 2H),2.81 (t, J=6 Hz, 2H), 2.72 (q, 6H), 2.11 (s, 3H), 2.06 (s, 3H), 1.8-1.6(m, 2H), 1.6-1.24 (m, 10H), 1.21 (s, 3H), 1.11 (t, J=7.2 Hz, 6H), 0.84<t, J=6.7 Hz, 3H); ¹³C NMR δ 168.3, 148.0, 147.5, 128.5, 127.4, 127.3,116.1, 75.6, 62.1, 51.6, 46.9, 39.8, 36.4, 31.8, 30.8, 29.7, 24.1, 23.5,22.5, 20.0, 14.0, 12.3, 12.1, 10.6; Anal. (C₂₆H₄₄N₂O₃) 1.5H₂O C,H,N.

EXAMPLE 14N-(3,4-dihydro-2-dodecyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0062] Use of3,4-dihydro-6-methoxy-2-dodecyl-2,7,8-trimethyl-2H-1-benzopyran-5-carboxylicacid as employed above afforded 0.839 (85%) of the desired compoundnamed above: ¹H NMR δ 6.6 (bs, 1H), 3.67 (s, 3H), 3.63-3.54 (m, 2H),2.77-2.6 (m, 8H), 2.15 (s, 3H), 2.09 (s, 3H), 1.75-1.65 (m, 2H),1.6-1.24 (m, 22H), 1.23 (s, 3H), 1.06 (t, J=7Hz, 6H), 0.84 (t, J=6.2 Hz,3H) Anal. (C₃₂H₅₆N₂O₃) C,H,N.

General Procedure for the Preparation of ofN-(3,4-dihydro-6-hydroxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-6-carbonyl)-N′,N′-dialkylethylenediamines

[0063] To an ice-cooled slurry of NaH (240 mg, 10 mmol) in 5 mL DMF wasadded EtSH (0.9 mL, 12 mmol) and the mixture was stirred for 15 min at0° C. A solution of the appropriateN-(3,4-dihydro-6-methoxy-2,2,7,8tetraalkyl-2H-1-benzopyran-5-carbonyl)-N′,N′-dialkylethylene diamine (1.24 mmol) in 10 mL DMF was added and the mixture wasstirred at 90° C. overnight. The mixture was then poured into H₂O andextracted with AcOEt. The organic layer was washed with brine, dried(Na₂SO₄) and the solvent was removed in vacuo. Purification by columnchromatography (CH₂Cl₂/MeOH 95:5) gave the title compounds.

EXAMPLE 15N-(3,4-dihydro-6-hydroxy-2,2,7,8-tetramethyl-2H-1-benzopyran-6-carbonyl)-N′,N′-diethylethylenediamine

[0064] Use ofN-(3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine as employed above afforded 0.42 g (97%) of the desiredcompound named above: ¹H NMR δ 6.8 (bs, 1H), 3.48 (bs, 1H), 2.82 (t,J=6.5 Hz, 2H), 2.64-2.52 (m, 6H), 2.12 (s, 3H), 2.09 (s, 3H), 1.68 (t,J=6.5 Hz, 2H), 1.28 (s, 6H), 1.0 (t, J=7.1 Hz, 6H); ¹³C NMR δ 170.0,149.6, 124.1, 114.0, 72.7, 51.1, 46.1, 36.9, 32.0, 26.8, 22.4, 12.4,11.9, 11.1; Anal. (C₂₀H₃₂N₂O₃). H₂O C,H,N.

EXAMPLE 16N-(3,4-dihydro-2-hexyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0065] Use ofN-(3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine as employed above afforded 0.48 g (93%) of the desiredcompound named above: ¹H NMR δ 6.74 (bs, 1H), 3.52 (bs, 2H), 2.84 (t,J=6Hz, 2H), 2.66-2.56 (m, 6H), 2.16 (s, 3H), 2.12 (s, 3H), 1.8-1.6 (m,2H); 1.6-1.28 (m, 10H), 1.25 (s, 3H), 1.01 (t, J=7 Hz, 6H), 0.87 (t,J=6.2 Hz, 3H); ¹³C NMR δ 170.1, 150.1, 144.5, 130.2, 124.2, 114.6,114.1, 74.8, 51.0, 46.1, 39.8, 36.9, 31.9, 31.3, 29.8, 24.1, 23.6, 22.6,22.3, 14.1, 12.5, 11.9, 11.3; Anal. (C₂₅H₄₂N₂O₃). 0.5H₂O C,H,N.

EXAMPLE 17N-(3,4-dihydro-2-dodecyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine

[0066] Use ofN-(3,4-dihydro-2-dodecyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N′,N′-diethylethylenediamine as employed above afforded 0.60 g (97%) of the desiredcompound named above: ¹H NMR δ 7.1 (bs, 1H), 3.56 (bs, 2H), 2.88 (t,J=6Hz, 2H), 2.69-2.60 (m, 6H), 2.16 (s, 3H), 2.12 (s, 3H), 1.75-1.58 (m,4H), 1.25 (m, 20H), 1.23 (s, 3H), 1.03 (t, J=7.1 Hz, 6H), 0.87 (t,J=6.3Hz, 3H); ¹³C NMR δ 170.1, 149.9, 144.5, 130.1, 124.2, 114.8, 114.1,74.7, 51.0, 46.1, 39.8, 36.7, 31.8, 31.3, 29.6, 29.3, 24.0, 23.6, 22.6,22.2, 14.0, 12.4, 11.9, 10.9; Anal. (C₃₁H₅₄N₂O₃) C,H,N.

General Procedure for the Preparation of3,4-dihydro-6-methoxy-5-nitro-2,2,7,8-tetraalkyl-2H-1-benzopyrans

[0067] 1.8 mL of acetyl nitrate (prepared from 0.4 mL HNO₃ 70% and 1,4mL Ac₂O at 0° C.) were added to a solution of the appropriate3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran (1.6 mmol) in 2mL Ac₂O and 2 mL AcOH at 0° C. The mixture was stirred at 0° C. for 1 hand then poured into ice-water. The aqueous mixture was extracted withAcOEt and the organic layer was washed with sat. aqu. NaHCO₃, brine anddried. The title compounds were purified by column chromatography (pet.ether/AcOEt 9:1)

EXAMPLE 183,4-dihydro-6-methoxy-6-nitro-2,2,7,8-tetramethyl-2H-1-benzopyran

[0068] Use of 3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyranas employed above afforded 0.40 g (94.8%) of the desired compound namedabove ¹H NMR δ 3.75 (s, 3H), 2.65 (t, J=6.6 Hz, 2H), 2.19 (s, 3H), 2.11(s, 3H), 1.75 (t, J=6.8 Hz, 2H), 1.32 (s, 6H) ¹³C NMR δ 147.9, 143.5,142.3, 130.0, 128.0, 74.3, 62.7, 31.6, 26.9, 26.7, 18.4, 12.6, 12.2Anal. (C₁₄H₁₉NO₄) C,H,N.

EXAMPLE 193,4-dihydro-6-methoxy-5-nitro-2-hexyl-2,7,8-trimethyl-2H-1-benzopyran

[0069] Use of3,4-dihydro-6-methoxy-2-hexyl-2,7,8-trimethyl-2H-1-benzopyran asemployed above afforded 0.40 g (74.5%) of the desired compound namedabove ¹H NMR δ 3.75 (s, 3H), 2.63 (t, J=6.7 Hz, 2H), 2.19 (s, 3H),2.11(s, 3H), 1.76-1.36 (m, 4H), 1.36-1.28 (m, 8H), 1.25 (s, 3H), 0.85(t, J=6.9 Hz, 3H) Anal. (C₁₉H₂₉NO₄) C,H,N.

General Procedure for the Preparation of5-amino-3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyrans

[0070] To a solution of3,4-dihydro-6-methoxy-5-nitro-2,2,7,8-tetraalkyl-2H-1-benzopyran (1.4mmol) in 15 mL EtOH were sequentially added CuCl (620 mg, 6.3 mmol) andNaBH₄ (480 mg, 12.6 mmol) at 0° C. The mixture was refluxed for 1 h,then cooled to RT, basified (NaHCO₃), filtered and washed with CH₂Cl₂.The filtrate was evaporated and the residue extracted with CH₂Cl₂ andwashed with brine. The organic layer was dried and the solvent wasremoved in vacuo.

EXAMPLE 205-amino-3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran

[0071] Use of3,4-dihydro-6-methoxy-5-nitro-2,2,7,8-tetramethyl-2H-1-benzopyran asemployed above afforded 0.279 (82.3%) of the desired compound namedabove ¹H NMR δ 3.69 (s, 3H), 3.58 (bs, 2H), 2.49 (t, J=6.8 Hz, 2H), 2.18(s, 3H), 2.05 (s, 3H), 1.82 (t, J=6.7 Hz, 2H), 1.31 (s, 6H). ¹³C NMR δ148.0, 138.7, 134.6, 127.6, 114.3, 104.7, 72.8, 59.7, 32.4, 26.7, 18.5,12.3, 11.1

EXAMPLE 215-amino-2-hexyl-3,4-dihydro-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran

[0072] Use of3,4-dihydro-2-hexyl-6-methoxy-5-nitro-2,7,8-trimethyl-2H-1-benzopyran asemployed above afforded 0.39 g (91.6%) of the desired compound namedabove ¹H NMR δ 3.67 (s, 3H), 3.55 (bs, 2H), 2.46 (t, J=6.8 Hz, 2H), 2.15(s, 3H), 2.03 (s, 3H), 1.9-1.65 (m, 2H), 1.55-1.5 (m, 2H), 1.5-1.27 (m,8H), 1.22 (s, 3H), 0.87 (t, J=6.6 Hz, 3H) ¹³C NMR δ 147.8, 139.0, 134.5,127.5, 114.4, 105.0, 74.8, 59.4, 39.6, 31.8, 30.8, 29.8, 23.8, 23.6,22.6, 18.2, 14.1, 12.3, 11.1

General Procedure for the Preparation ofN-(3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-yl)-bromoacetamides

[0073] To a solution of5-amino-3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran (1.28mmol) in 8 mL THF were added 1 mL BrCH₂COCl and triethylamine at 0° C.After been stirred at RT for 1 h the mixture was poured into H₂O andextracted with AcOEt. The organic layer was washed with sat. aqu.NaHCO₃, brine and dried.

EXAMPLE 22N-(3,4-dihydro-2-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-6-yl)-bromoacetamide

[0074] Use of5-amino-3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran asemployed above afforded 0.43 g (94.9%) of the desired compound namedabove

[0075]¹H NMR δ 7.88 (bs, 1H), 4.05 (s, 2H), 3.63 (s, 3H), 2.58 (t, J=6.6Hz, 2H), 2.17 (s, 3H), 2.09 (s, 3H), 1.72 (t, J=6.7 Hz, 2H), 1.31 (s,6H) ¹³ C NMR δ 164.4, 148.0, 128.3, 125.2, 116.5, 73.7, 61.1, 32.3,29.0, 26.9, 19.4, 12.4, 12.0

EXAMPLE 23N-(3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-yl)-bromoacetamide

[0076] Use of5-amino-3,4-dihydro-6-methoxy-2-hexyl-2,7,8-trimethyl-2H-1-benzopyran asemployed above afforded 0.50 g (92%) of the desired compound named above¹H NMR δ 7.9 (bs, 1H), 4.04 (s, 2H), 3.63 (s, 3H), 2.56 (t, J=6.5 Hz,2H), 2.17 (s, 3H), 2.09 (s, 3H), 1.8-1.65 (m, 2H), 1.65-1.5 (m, 2H),1.48-1.27 (m, 8H), 1.23 (s, 3H), 0.86 (t, J=6.7 Hz, 3H) ¹³C NMR δ 164.4,148.3, 145.7, 128.2, 125.2, 124.5, 116.8, 75.7, 61.0, 53.4, 40.0, 31.8,30.7, 29.8, 29.0, 23.9, 23.6, 22.6, 19.0, 14.1, 12.4,12.0

General Procedure for the Preparation ofN-(3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-yl)-(dialkylamino)acetamides

[0077] To a solutionN-[3,4-dihydro-6-methoxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-yl]-bromoacetamide(1.18 mmol) in 7 mL toluene at 0° C. was added 3 mmol dialkylamine.After stirring for 2 days at RT the mixture was extracted with 2N HCl.The aqueous layer was made basic with 2N NaOH and extracted with CH₂Cl₂.The organic layer was dried and evaporated,

EXAMPLE 24N-(3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide

[0078] Use ofN-(3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-yl)-bromoacetamideas employed above afforded 0.29 g (72%) of the desired compound namedabove. ¹H NMR δ 8.97 (bs, 1H), 3.59 (s, 3H), 3.19 (s, 2H), 2.66 (q, 6H),2.59 (t, J=6.7 Hz, 2H), 2.16 (s, 3H), 2.08 (s, 3H), 1.71 (t, J=6.7Hz,2H), 1.30 (s, 6H), 1.13 (t, J=7.1 Hz, 6H) ¹³C NMR δ 170.7, 148.3, 145.8,128.0, 125.4, 124.3, 116.6, 73.5, 60.9, 57.7, 48.9, 32.5, 26.9, 19.6,12.4, 12.3, 11.9

EXAMPLE 25N-(3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide

[0079] Use ofN-(3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-yl)-bromoacetamideas employed above afforded 0.36 g (74.5%) of the desired compound namedabove.

[0080]¹H NMR δ 8.96 (bs, 1H), 3.59 (s, 3H), 3.19 (s, 2H), 2.66 (q, 6H),2.57-2.50 (m, 2H), 2.16 (s, 3H), 2.07 (s, 3H), 1.8-1.56 (m, 4H),1.5-1.27 (m, 8H), 1.23 (s, 3H), 1.12 (t, J=7.1 Hz, 6H) 0.86 (t, J=6.5Hz, 3H) ¹³C NMR δ 170.7, 149.0, 145.7, 128.0, 125.4, 124.3, 116.8, 75.5,60.9, 57.6, 48.8, 40.0, 31.8, 30.8, 29.8, 23.9, 23.6, 22.6, 19.2, 14.1,12.5, 12.4, 11.8

General Procedure for the Preparation of(3,4-dihydro-6-hydroxy-2,2,7,8-tetraalkyl-2H-1-benzopyran-5-yl)-(dialkylamino)acetamides

[0081] The deprotection of the methoxy group was carried out followingthe general procedure for d-e. The amides were purified by columnchromatography (CH₂Cl₂/MeOH 95:5):

EXAMPLE 26N-(3,4-dihydro-6-hydroxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide

[0082] Use ofN-[3,4-dihydro-6-methoxy-2,2,7,8-tetramethyl-2H-1-benzopyran-yl]-bromoacetamide(0.72 mmol) afforded 0.19 g (81%) of the desired compound named above.¹H NMR δ 9.5 (bs, 1H), 8.27 (bs, 1H), 3.23 (s, 2H), 2.69 (q, 6H), 2.54(t, J=6 Hz, 2H), 2.20 (s, 3H), 2.09 (s, 3H), 1.79 (t, J=7Hz, 2H), 1.23(s, 6H), 1.09 (t, J=7 Hz, 6H); ¹³C NMR δ 171.2, 145.1, 140.8, 126.2,124.0, 120.4, 109.3, 72.5, 57.4, 48.6, 32.4, 26.5, 19.4, 12.4, 12.3,11.8 Anal. (C₁₉H₃₀N₂O₃) C,H,N.

EXAMPLE 27N-(3,4-dihydro-2-hexyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide

[0083] Use ofN-(3,4-dihydro-2-hexyl-6-methoxy-2,7,8-trimethyl-2H-1-benzopyran-yl)-bromoacetamide(0.5 mmol) afforded 0.12 g (62%) of the desired compound named above.

[0084]¹H NMR δ 9.5 (bs, 1H), 8.27 (bs, 1H), 3.24 (s, 2H), 2.69 (q, 6H),2.53 (t, J=6 Hz, 2H), 2.20 (s, 3H), 2.09 (s, 3H), 1.8-1.65 (m, 2H),1.6-1.26 (m, 10H), 1.21 (s, 3H), 1.09 (t, 6H), 0.86 (t, 3H); ¹³C NMR δ171.2, 145.0, 140.8, 126.2, 124.1, 120.4, 109.5, 73.7, 57.4, 48.6, 39.4,31.8, 31.0, 29.7, 23.6, 23.5, 22.6, 19.1, 14.0, 12.4, 11.8 Anal.(C₂₄H₄₀N₂O₃) C,H,N.

General procedure for the Preparation of2,3-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-4H-1-benzopyran-4-ones

[0085] To a solution of 2,4,5-trialkyl-3,6-dihydroxyacetophenone (15mmol) in 15 mL absolute ethanol was added the appropriate ketone (15mmol), pyrrolidine (45 mmol) and powdered 3 Å molecular sieves (2.5 g).The resulting mixture was heated at 50-60° C. overnight. The reactionmixture was pourred to ice, 10N HCl was added and the mixture wasextracted with ether. The organic layer was extracted with sat. aq. NaCland was dried with anhydrous Na₂SO₄. The solvent was evaporated in vacuoand the crude product was purified by flash column chromatography usingthe appropriate mixture of pet. ether/ethyl acetate as eluting solvent.

EXAMPLE 282,3-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-4H-1-benzopyran-4-one

[0086] Use of 2,4,5-trimethyl-3,6-dihydroxyacetophenone and acetone asemployed above afforded 1.59 g (38%) of the desired compound namedabove: ¹H NMR: δ 11.90 (s, 1H), 2.65 (s, 2H), 2.16 (s, 3H), 2.07 (s,3H), 2.03 (s, 3H), 1.41 (s, 6H); ¹³C NMR: δ 198.17, 156.87, 154.14,147.62, 115.30, 114.50, 104.96, 77.88, 47.92, 26.65, 16.93, 11.18, 10.53

EXAMPLE 292,3-dihydro-2-hexyl-6-hydroxy-2,5,7,8-trimethyl-4H-1-benzopyran-4-oneUse of 2,4,5-trimethyl-3,6-dihydroxyacetophenone and 2-octanone asemployed above afforded 3.22 g (62%) of the desired compound namedabove: ¹H NMR: δ 11.95 (s, 1H), 2.72, 2.59 (AB q, J=16.88 Hz, 2H), 2.18(s, 3H), 2.08 (s, 3H), 2.06 (s, 3H), 1.48-1.73 (m, 2H), 1.35 (s, 3H),1.35-1.16 (b s, 8H), 0.83 (t, J=6.3 Hz, 3H); ¹³C NMR: δ 198.63, 157.05,154.56, 147.90, 115.49, 114.75, 105.43, 80.26, 47.12, 39.56, 31.82,29.60, 24.10, 23.65, 22.68, 17.24, 14.17, 11.42, 10.81. GeneralProcedure for the Preparation of2,3-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-4H-1-benzopyran-4-one-oximes

[0087] To a solution of the appropriate2,3-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-4H-1-benzopyran-4-one (0.77mmol) in dry pyridine 5 mL was added hydroxylamine hydrochloride (890mg, 12.8 mmol) and the resulting mixture was stirred at 70° C.overnight. After cooling the reaction mixture to room temperature thepyridine was evaporated in vacuo and the residue was taken up with ethylacetate. The organic layer was extracted with water and sat. aq. NaCland was dried with anhydrous Na₂SO₄. The solvent was evaporated in vacuoand the crude product was used without further purification for the nextstep.

EXAMPLE 302,3-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-4H-1-benzopyran-4-one-oxime

[0088] Use of2,3-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-4H-1-benzopyran-4-one asemployed above afforded 0.224 g (100%) of the desired compound namedabove: ¹H NMR: δ 10.97 (s, 1H), 7.50 (b s, 1H), 2.88 (s, 2H), 2.18 (s,3H), 2.14 (s, 3H), 2.07 (s, 3H), 1.37 (s, 6H); ¹³C NMR: δ 155.67,152.76, 140.14, 124.50, 115.25, 109.80, 100.81, 74. 21, 33.71, 26.89,16.46, 11.47, 11.34.

EXAMPLE 312,3-dihydro-2-hexyl-6-hydroxy-2,5,7,8-trimethyl-4H-1-benzopyran-4one-oxime

[0089] Use of2,3-dihydro-2-hexyl-6-hydroxy-2,5,7,8-trimethyl-4H-1-benzopyran-4-one asemployed above afforded 0.278 g (100%) of the desired compound namedabove: ¹H NMR: δ 11.10 (s, 1 H), 2.87 (s, 2H), 2.18 (s, 3H), 2.14 (s,3H), 2.07 (s, 3H), 1.52-1.72 (m, 2H), 1.35-1.43 (m, 2H), 1.31 (s, 3H),1,26 (b s, 6H), 0.86 (t, J=6.4 Hz, 3H); ¹³C NMR: δ 155.29, 152.74,139.84, 124.10, 115.14, 115.042, 109.74, 101.16, 76.29, 39.49, 32.57,31.74, 29.57, 24.05, 23.55, 22.56, 16.42, 14.05, 41.45, 11.34.

General Procedure for the Preparation of4-amino-3,4-dihydro-2,2,5,7,8-pentaalkyl-2H-1-benzopyran-4-ols

[0090] To a solution of TiCl₄ (0.17 mL, 1.53 mmol) in dimethoxyethane (2mL) at 0° C. was added NaBH₄ (116 mg, 3.06 mmoles). The mixture wasstirred at 0° C. for 10 minutes and subsequently a solution of theappropriate2,3-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-4H-1-benzopyran-4-one-oxime(0.51 mmoles) in 2 ml dimethoxyethane was added dropwise. The mixturewas stirred at room temperature overnight. The reaction mixture wascooled to 0° C. and water was added. The mixture became basic with theaddition of 28% aqueous ammonia and was extracted with methylenechloride. The organic layer was extracted with sat. aq. NaCl and wasdried with anhydrous Na₂SO₄ and the solvent was evaporated in vacuo. Theproduct was used as such for the next step.

EXAMPLE 324-amino-3,4-dihydro-2,2,5,7,8-pentamethyl-2H-1-benzopyran-6-ol

[0091] Useof2,3-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl4H-1-benzopyran-4-one-oximeas employed above afforded 74 mg (52%) of the desired compound namedabove: ¹H NMR: δ 4.16-4.10 (m, 1H), 2.14 (s, 3H), 2.11 (s, 3H), 2.04 (s,3H), 2.22-1.99 (m, 2H), 1.38 (s, 3H), 1.19 (s, 3H).

EXAMPLE 334-amino-3,4-dihydro-2-hexyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol

[0092] Use of2,3-dihydro-2-hexyl-6-hydroxy-2,5,7,8-trimethyl-4H-1-benzopyran4-one-oximeas employed above afforded 97 mg (55%) of the desired compound namedabove: ¹H NMR: δ 4.20-4.15 (m, 1H), 2.18 (s, 3H), 2.12(s, 3H), 2.03 (s,3H), 2.22-2.01 (m, 2H), 1.78-1.15 (m, 13H), 0.85 (t, J=6.4 Hz, 3H).

General Procedure for the Preparation ofN-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-2H-1-benzopyran-4-yl)-bromoacetamides

[0093] The 4-amino-3,4-dihydro-2,2,5,7,8-pentaalkyl-2H-1-benzopyran-6-ol(0.3 mmol) was dissolved in a mixture of tetrahydrofuran/water. To thesolution was added NaHCO₃ and the appropriate acid chloride dropwiseuntil the starting material had dissappeard. The mixture was taken up indichloromethane and the organic layer was extracted sequentially withsaturated aq. NaHCO₃ and saturated aq. NaCl and was dried with anhydrousNa₂SO₄ and the solvent was evaporated in vacuo. The product was purifiedby flash column chromatography using the appropriate mixture ofpetroleum ether/ethyl acetate as eluent.

EXAMPLE 34N-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran4-yl)-bromoacetamide

[0094] Use of4-amino-2,2,5,7,8-pentamethyl-3,4-dihydro-2H-1-benzopyran-6-ol asemployed above afforded 0.1 g (82%) of the desired compound named above:¹H NMR: δ 6.5 (b s 1H), 5.15-5.05 (m, 1H), 3.88 (s, 2H), 2.21 (s. 3H),2.12 (s, 3H), 2.11 (s, 3H), 2.22-1.98 (m, 2H), 1.32 (s, 3H), 1.25 (s,3H),

EXAMPLE 35N-(3,4-dihydro-2-hexyl-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-4-yl)-bromoacetamide

[0095] Use of4-amino-2-hexyl-2,5,7,8-tetramethyl-3,4-dihydro-2H-1-benzopyran-6ol asemployed above afforded 0.110 g (79%) of the desired compound namedabove: ¹H NMR: δ 7.12 (bs, 1H), 5.20-5.10 (m, 1 H), 3.81 (s, 2H), 2.15(s, 3H), 2.05 (s, 3H), 2.01 (s, 3H), 2.18-1.99 (m, 2H), 1.75-1.12 (m, 13H), 0.85 (t, J=6.4 Hz, 3H).

General Procedure for the Preparation ofN-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-2H-1-benzopyran-4-yl)-(dialkylamino)acetamide

[0096] Use ofN-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentaalkyl-2H-1-benzopyran-4-yl)-bromoacetamidesas described for the preparation of Examples 24 and 25 affords thedesired compounds.

EXAMPLE 36N-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran-4-yl)-(diethylamino)acetamideUse ofN-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran4-yl)-bromoacetamideas employed above afforded 93 mg (95%) of the desired compound namedabove: ¹H NMR: δ 8.41 (s, 1H), 8.22 (d, J=8.46 Hz, 1H), 5.17-5.11 (m,1H), 3.10, 3.05 (AB q. J=17.48 Hz, 2H), 2.52 (q, J=7.04 Hz, 4H),2.22-2.01 (m, 1H), 2.16 (s, 3H), 2.13 (s, 3H), 2.07 (s, 3H), 1.85-1.80(m, 1H), 1.45.(s, 3H), 1.39 (s, 3H), 0.97 (t, J=7.05 Hz, 6H); ¹³C NMR: δ173.8, 151.28, 148.88, 136.89, 128.93, 128.13, 115.20, 105.06, 72.37,56.99, 48.41, 39.92, 39.82, 28.50, 26.92, 16.02, 12.22, 11.85, 11.52EXAMPLE 37N-(3,4-dihydro-2-hexyl-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-4-yl)-(diethylamino)acetamide

[0097] Use of N-(3,4-dihydro-2-hexyl-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-4-yl)-bromoacetamide as employedabove afforded 0.102 g (94%) of the desired compound named above: ¹HNMR: δ 8.47 (s), 8.22 (d, J=9.1 Hz), 8.11 (s), 8.00 (d, J=9.2 Hz),5.17-5.13 (m, 1H), 3.09-3.02 (m, 2H), 2.52 (q, J=7.12 Hz, 4H), 2.16 (s,3H), 2.13 (s, 3H), 2.07 (s, 3H), 2.11-2.02 (m, 1H), 1.92-1.85 (m, 1H),1.79-1.25 (m, 13 H), 0.97 (t, J=7.14 Hz, 6H), 0.85 (t, J=6.7 Hz, 3H);¹³C NMR: δ 174.01, 173.86, 151.27, 151.15, 148.97, 148.78, 136.91,136.77, 115.44, 115.21, 115,11, 105.44, 105.27, 75.00, 74.35, 60.33,57.04, 56.81, 48.57, 48.44, 41.25, 39.93, 39.80, 39.66, 39.50, 38.33,31.71, 29.71, 29.59, 24.55, 24.34, 23.72, 23.37, 22.56, 16.03,14.01,12.27, 12.10, 11.86, 11.53.

[0098] As previously mentioned, the compounds of the present inventioncombine antioxidant and antiarrhythmic activity. They could also beuseful for the treatment of a variety of disorders related to freeradicals and/or arrhythmias. It should be noted that reference herein totreatment extends to prophylaxis as well as the treatment of establisheddiseases,

[0099] The antioxidant activity of the new compounds was initiallyevaluated as set forth below.

[0100] In vitro lipid peroxidation (Bationi J. P., Fontecave M., JaouenM., Mansuy D. “Vitamin E derivatives as new potent inhibitors ofmicrosomal lipid peroxidation” Biochem. Biophys. Res. Com. 1991, 174,1103)

[0101] For these experiments, heat-inactivated hepatic microsomalfraction from untreated Fischer rats (200-220 g), corresponding to 0.125g liver/ml final volume, was used. The incubation mixture contained themicrosomal fraction, ascorbic acid (0.2 mM), in Tris buffer (50 mM, pH7.4) and various concentrations (5 μM-1 mM) of the examined compoundsdissolved in DMSO. The lipid peroxidation reaction was initiated withthe addition of a freshly prepared FeSO₄ solution (10 μM) and aliquotswere taken at various time intervals for 45 min. Lipid peroxidation wasestimated spectroscopically (535 nm vs. 600 nm) as 2-thiobarbitouricacid (TBA) reactive material. Each experiment was performed at least intriplicate.

[0102] The effect of various concentrations of representative compoundsof the present invention on lipid peroxidation is shown in Table 1. Allthe tested compounds demonstrated significant antioxidant activity. atthe micromolar range. However, there are quantitative differences thatappear to be connected with the position of the amide substituent andthe length of the side chain. TABLE 1 Compound Concentration μM %Inhibition a 10 96.3 b 10 7.7 b 50 91 c 200 0 c 400 48.6 c 500 93.8 d 1038.4 d 50 98.1 e 50 87.4 f 50 0 f 1000 100 g 10 100 g 5 72.4 h 10 100 h5 17.4 i 50 98.6 j 50 96.1 Vitamin E 10 21 Trolox 10 49

[0103] The evaluation of the antiarrhythmic activity of the compoundsset forth above was carried out on isolated heart preparations using theKrebs perfused Langerdorff model (Heisier B. E., Ferrier G. R.“Proarrhythmic actions of flecainide in an isolated tissue model ofischemia and reperfusion” J. Pharmacol. Exp. Ther. 1996, 279, 317). MaleWistar rats, 250-300 g, were anesthetized with pentobarbitone (15mg/rat=5 mg/100 g body weight) and heparinized (1000 IU)

[0104] Hearts were excised and washed in ice cold modifiedKrebs-Henseleit (KHB) buffer of the following composition in mM: NaCl118, KCl 4.7, NaHCO₃ 25, KH₂PO₄ 1.2, MgSO₄ 1.4, CaCl₂ 2.5, Glucose 11.Hearts were mounted on a Langerdorff apparatus, perfused at a pressure100 mmHg, at 37° C., with KHB (9 ml/min) for 30-40 min and then the“ischemic” KHB solution was applied for 15 min (this solution is a KHbuffer in which the glucose is substituted by Tris HCl. The hearts werethen perfused with normal KHB for 30 min. Drugs were present during thelast 5 min of ischemia and during reperfusion at the final concentrationof 30 or 100 μM. Electrocardiograms were recorded during equilibraton,ischemia and reperfusion. The most important arrhythmias seem to occurduring early reperfusion (Li G-R., Ferrier G. R. “Effects of lidocaineon reperfusion arrhythmias and electrophysiological properties in anisolated ventricular muscle model of ischemia. and reperfusion” J.Pharmacol. Exp. Ther. 1991, 257, 997). Table 2 shows the incidence ofarrhythmias during the reperfusion period for selected examples. TABLE 2Incidence of arrhythmias during the reperfusion period Compound (30 μM)(100 μM) control 12 ± 4  (no drug present) a   7 ± 3.5 5 ± 2 g   8 ± 2.17 ± 2 h 6 ± 3   6 ± 2.5

1. A compound of Formula I

wherein X═CH₂, NC(O)CH₂N R′R″, CHNHC(O)CH₂NR′R″, NC(O)R′″, CHNHC(O)R′″,n=1 X═CH₂, N=0 R₁=H, alkyl, alkenyl, alkynyl, aryl all of which may beoptionally substituted R₂=Alkyl, aryl, C(O)Y C(O)R′″, CH₂Y(CO)R′″,CH₂YCH₂R′″ R₃=Alkyl, C(O)NH(CH₂CH₂)_(m)N R′R″, NHC(O)CH₂N R′R″,NHC(O)R′″ R₄, R₅=Lower alkyl Y=HN(CH₂CH₂)_(m)NH, HNCHR₁NH,HN-cycloalkyl-NH, HN-aryl-NH, heterocyclic diamine, m=1-5 R′, R″=AlkylR′″=(methylsulfonyl)amino-N-aryl
 2. A compound according to claim 1wherein X═CH₂ n=1 R₁=Me, R₂=Alkyl R₃=CONHCH₂CH₂N Et₂ R₄, R₅=Me
 3. Acompound according to claim 1 wherein X═CH₂ n=1 R₁=Me, R₂=AlkylR₃=NHCOCH₂N Et₂ R₄, R₅=Me
 4. A compound according to claim 1 whereinX═CH₂NHCOCH₂N Et₂ n=1 R₁=Me, R₂=Alkyl R₃, R₄, R₅=Me
 5. A compoundaccording to claim 2 wherein the compound is selected from one of thefollowing:N-(3,4dihydro-6-hydroxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-carbonyl)-N′N′-diethylethylenediamineN-(3,4-dihydro-2-hexyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N,N′-diethylethylenediamineN-(3,4-dihydro-2dodecyl-6-hydroxy-2,7,8-trimethyl-2H-1-benzopyran-5-carbonyl)-N,N′diethylethylenediamine
 6. A compound according to claim 3 wherein the compoundis selected from one of the following:N-(3,4-dihydro-6-hydroxy-2,2,7,8-tetramethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamideN-(3,4-dihydro-6-hydroxy-2-hexyl-2,7,8-trimethyl-2H-1-benzopyran-5-yl)-(diethylamino)acetamide
 7. A compound according to claim 4 wherein the compound isselected from one of the following:N-(3,4-dihydro-6-hydroxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran4-yl)(diethylamino)acetamideN-(3,4-dihydro-6-hydroxy-2-hexyl-2,5,7,8-tetramethyl-2H-1-benzopyran-4-yl)(diethylamino) acetamide
 8. Compounds of Formula I combine the keyfeatures responsible for the activity of class I or III antiarrhythmicswith nuclei possessing antioxidant properties and are effective inreducing reperfusion arrhythmias.
 9. Pharmaceutical formulationscontaining compounds of Formula I and their acceptable salts.